Boat trailers for carrying monohull craft over land have a wishbone plan frame-chassis which is welded or bolted together from straight stock or formed from straight stock to produce a narrow neck hitch end of the trailer and a broad section between the trailer wheels that carries the hull.
Conventional wishbone design boat trailers have side rails of steel or aluminum, or fiberglass pulltrusions, and a conventional beam-stress design of two flanges or flange areas separated by a web area. Between the wishbone chassis frame and the boat hull is a system of cribbing or numerous rollers permanently attached to the trailer.
These conventional trailers have two principal drawbacks: (1) They duplicate the fore-aft stiffness of the carried craft's hull, thereby making the trailer excessively heavy and difficult to tow with today's lighter weight cars; (2) Their chassis-frame uses conventional beam-stress design wherein the chassis side rail flanges are alternately in compression and tension are uniform in beam strength.
The object of the present invention is to avoid these problems by providing a much lighter weight chassis-frame design (about half (1/2) the weight of most metal trailers), cast in laminate or formed in metal and reinforced.